
<template>
    <div id="app">
      <h1>{{ message }}</h1>
      <button @click="changeMessage">Change Message</button>
    </div>
  </template>
  
  <script>
  import { ref } from 'vue';
  
  export default {
    setup() {
      const message = ref('Hello Vue 3!');
  
      function changeMessage() {
        message.value = 'Message changed!';
      }
  
      return {
        message,
        changeMessage,
      };
    },
  };
  </script>
  
  <style>
  #app {
    font-family: Avenir, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-align: center;
    color: #2c3e50;
    margin-top: 60px;
  }
  </style>